Odds Converter

What are sportsbook odds?

Sportsbook odds are the price you pay to take a bet. They tell you two things: how much you win if your pick comes through, and what probability the bookmaker assigns to that outcome happening. Four common formats encode the same underlying numbers differently — American, Decimal, Fractional, and Implied Probability. The converter above handles all four.

Reading negative vs positive American odds

American odds are common in US sportsbooks. A negative number (e.g. −110) means you must risk that amount to win $100. So −110 = risk $110 to win $100. A positive number (e.g. +150) means you win that much on a $100 bet. So +150 = bet $100, win $150 profit.

The sign tells you who’s favored: negative = the bookmaker thinks this outcome is more likely than 50%; positive = less likely than 50%. The further from +100 / −100 (which is the even-money line), the more lopsided the bookmaker thinks the matchup is.

What implied probability really tells you

Implied probability is the probability of the outcome that breaks even on a fair bet at those odds. 2.00 decimal odds (or +100 American) implies a 50% probability — a fair coin flip. 1.91 decimal (or −110 American) implies 52.4%.

Importantly, implied probability is notthe bookmaker’s actual belief about what will happen. It includes the bookmaker’s margin — the “vig” or “juice”. Two sides of a coin flip both quoted at 1.91imply 52.4% each — total 104.8% — with the 4.8% being the bookmaker’s edge. Sum the implied probabilities of all outcomes in any market and you’ll see the total exceeds 100%; that excess is the vig.

When to use each format

Decimal is easiest for math — multiply your stake by the decimal to get total return. American is what US sportsbooks publish — useful for parsing favored vs underdog at a glance. Fractional is traditional UK format — most useful for converting to mental odds (3/2 = 60% chance to lose, 40% chance to win). Implied probabilityis the format you want when comparing the bookmaker’s assessment to your own.

For the math behind these conversions and what bookmaker margin does to the implied probabilities you read, see our odds conversion methodology.